Mixtures
Which type of mixture has visible parts?
Heterogeneous
Which type of change is usually reversible?
physical
How many Oxygen atoms are in H2O?
1
What do you call the substances that are on the lefthand side of a chemical equation?
the reactants
What is the density of water?
1 g/cm3
Which type of mixtures contains parts that are not all visible?
Homogenous
Rust forming on iron is an example of which type of change?
Chemical
TRUE OR FALSE: According to the Law of Conservation of Mass, if a reaction starts with 50 atoms it will end with more atoms as new substances are being made.
False
What is needed to start any chemical reaction?
Energy
Why does hot water rise above cold water?
Because it is less dense - molecules are more spread out
When salt dissolves into water to make a solution, the salt is considered to be a...
Solute / Soluble substance
Changing states of matter is an example of which type of change?
Physical
What does a subscript tell you?
Small number written on lower right of the symbol.
Shows there is more than one atom of that element
What type of reaction takes IN heat at the end?
Endothermic
Calculate the density of an object that has a mass of 50 g and a volume of 25 cm3. Will it sink or float in water?
2 g/cm3 - sink
What are the different types of heterogenous mixtures called?
Suspensions & Colloids
Properties of matter that can be seen or measured without changing the substance into something else are called
Physical Properties
How many oxygen atoms are present in the compound Al2(SO4)3?
12
What are 4 indicators that a chemical reaction has occured?
1. production of energy (light/heat)
2. formation of a precipitate
3. color change/odor change
4. bubbling/fizzing
Honey has a density of 1.35 g/cm3, water has a density of 1 g/cm3 and rubbing alcohol has a density of 0.93 g/cm3. If a popcorn kernel with a density of 1.2 g/cm3 was dropped, where would it fall to?
The bottom of the water layer.
Give an example of a colloid
Milk, Paint, Fog
Which property can be used to identify a substance?
Density
Boiling/Melting Point
Reactivity
How many TOTAL atoms are present in the compound 2C6H12O6?
48
What are 5 ways to speed up a chemical reaction?
1. catalyst
2. concentration
3. pressure
4. temperature
5. surface area
What is it called if an object isn't quite floating at the top and not sinking in a liquid?
suspending